In order to have an indication of the water level in the tank in these abnormal conditions, it has been proposed to provide instrumentation on the cover of the tank by means of the usual water level detection devices, for example, ultrasonic emitter-receivers. However, this instrumentation is difficult to realize on account of the thickness of the cover and must be capable of withstanding the same physical conditions as the latter, in particular, high pressure and temperature.
It is an object of the invention to provide a device which overcomes this problem.
It is a further object to provide a device which enables the use for this purpose of certain adapter tubes of the actuacting mechanisms of the control rods.
It is in fact known that the cover of the reactor tank is traversed by a certain number of vertical tubes of inconel welded to the cover and to the upper part to which the actuating mechanisms of the control rods are adapted.
Normally, all the adapter tubes are not used at the same time and those which are not provided with actuating mechanisms are each closed by a plug, enabling the fluid tightness of the tank to be preserved.